Most synthetic traffic (i.e. traffic that does not represent a real person or computer making a real request of a service we host) is dropped at the edge of our network due to our advanced network and firewall architecture. This protects our members' services from several types of denial-of-service attacks.

If you attempt to ping something on our network (e.g. your web site) you may get a response. However, this response is a fake generated by our firewall and does not necessarily indicate that your site is reachable. We do sharply limit the number of outbound ICMP ping replies we send at any given time, which can mean your ping requests won't even get fake replies if someone is ping-flooding us; attempts to ping-flood us are very common and completely ineffective, largely because of precautions like these. For that reason, don't assume the (in)ability to ping your site reflects on whether or not it is working properly.

Some traceroute applications, like most under Unix, use UDP packets to probe network hops. These applications will show a "filter prohibited" response (usually "!X") or a routing loop at the edge of our network. Others, most notably the tracert.exe provided with Windows, use ICMP to probe network hops and may be fooled by our fake ping responses. Both results are normal and should not be used as the basis for a problem report.

If you need to traceroute to our network to diagnose an intermediate connection issue, you can use the hostname traceroute.nearlyfreespeech.net for this purpose.

For an accurate measure of your site's performance and availability, you should complete an actual HTTP request to the site, checking both that it responds correctly and how long that response takes. This would be true even if we weren't playing games with ping and traceroute, because overloaded or malfunctioning servers often respond quickly to pings but slowly or not at all to real traffic. Various utilities exist that can be used to test HTTP servers, such as wget, curl, and fetch.